Abstract
Highly sensitive and selective hydrogen sulfide (H2S) sensors based on hierarchical highly ordered SnO2 nanobowl branched ZnO nanowires (NWs) were synthesized via a sequential process combining hard template processing, atomic-layer deposition, and hydrothermal processing. The hierarchical sensing materials were prepared in situ on microelectromechanical systems, which are expected to achieve high-performance gas sensors with superior sensitivity, long-term stability and repeatability, as well as low power consumption. Specifically, the hierarchical nanobowl SnO2@ZnO NW sensor displayed a high sensitivity of 6.24, a fast response and recovery speed (i.e., 14 s and 39 s, respectively), and an excellent selectivity when detecting 1 ppm H2S at 250 °C, whose rate of resistance change (i.e., 5.24) is 2.6 times higher than that of the pristine SnO2 nanobowl sensor. The improved sensing performance could be attributed to the increased specific surface area, the formation of heterojunctions and homojunctions, as well as the additional reaction between ZnO and H2S, which were confirmed by electrochemical characterization and band alignment analysis. Moreover, the well-structured hierarchical sensors maintained stable performance after a month, suggesting excellent stability and repeatability. In summary, such well-designed hierarchical highly ordered nanobowl SnO2@ZnO NW gas sensors demonstrate favorable potential for enhanced sensitive and selective H2S detection with long-term stability and repeatability.
Highlights
Hydrogen sulfide (H2S), one of the most dangerous hazardous gases, has aroused widespread concern for its severe toxicity to the human body as well as being normally generated from industries[1,2,3]
A new strategy of seamlessly integrating nanomaterials and microhotplatforms for the sensor fabrication process is of vital importance for obtaining high-performance gas sensors with excellent stability and repeatability, as well as low power consumption
Highly ordered monolayer polystyrene (PS) spheres soaked with SnCl4 precursor solution were obtained on a PS spheres
Summary
Hydrogen sulfide (H2S), one of the most dangerous hazardous gases, has aroused widespread concern for its severe toxicity to the human body as well as being normally generated from industries[1,2,3]. Among various investigated SMOs, tin-oxide (SnO2) nanomaterials with different morphologies, such as nanoparticles[9], nanowires (NWs)[10], nanofibers[11], and nanobamboos[12], have been intensively explored and regarded as the most promising candidates for highperformance gas sensors, with numerous merits, such as high carrier mobility, great chemical and thermal stability, and low cost[13,14]. Such a highly ordered monolayer macroporous structure demonstrated enhanced gas response and response speed due to its large specific surface area and well-interconnected pore structure[18]
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